Spirit-level



(No Model.)

B. LEWIS & P. ARMSTRONG.

SPIRIT LEVEL.

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lI Nirn Srarns arnNT OFFICE.

EVAN LEWVIS AND FREDERICK ARMSTRONG, OF KINGSTQN, PENNSYLVANIA.

SPIRIT-LEVEL.

SPECIFICATION forming part of Letters Patent No. 401,843, dated April23, 1889.

Application filed January 9, 1889. Serial No. 295,897. (No model.)

To all whom it may concern.-

Be it known that we, EVAN LEWIS and FREDERICK ARMSTRONG, both citizensof the United States, residing at Kingston, in the county of Luzerne andState of Pennsylvania, have invented certain new and useful Improvementsin Spirit -Levels; and we do declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same,reference being had to the accompanying drawings, and to the letters andfigures of reference marked thereon, which form a part of thisspecification.

Our invention relates to an improvement in spirit-levels, and moreparticularly to means for securing the spirit-tube in place on the stockof the level.

I-Ieretofore it has been usual to embed the glass spirit-tube in amixture of plaster-ofparis and water, the plaster being thus renderedsemi-fluid' This plastic composition becoming hard by the ultimateevaporation of the water secures the tube rigidly in place. It requiresdexterity only acquired by practical experience to properly set aspirit-tube in the wooden level-stock, as it must be given a veryaccurate adjustment with regard to its air-bubble so as to locate thelatter directly at the center of length of the tube when the stock is ina true horizontal plane. The embedding of a spirit-tube inplaster-of-paris, as just stated, is also objectionable, from the factthat the tube is liable to be fractured from percussion, as the contactof the tube with the plaster and the latter-named with the levelstock isinelastic. Consequently accidental shocks sustained by the instrument inuse-such as falling from an elevation-will be liable to crack thespirit-tube and render the level useless until a new tube is substitutedfor the broken one.

The primary object of our present invention is to provide a convenientdevice for holding the spirit-tube in place on a levelstock, which, fromits manner of construction, will facilitate the embedding accurately ofsaid tube, While a sufficient degree of elasticity is afforded toobviate fracture of the same from shock or percussion of the stock.

A further object is to furnish a cheap and reliable attachment for aspirit-level and plumb, which will enable an ordinary mechanic to setanew spirit-tube inalevel-stock without the use of plaster-of-paris orsimilar plastic material that sets and becomes rigid and inelastic.

lVith these objects in View our invention consists in certain featuresof construction and combinations of parts, which will be hereinafterdescribed, and pointed out in the claims.

Referring to the drawings making a part of this specification, Figure 1is a side view of a portion of a level-stock having our improvementmounted thereon. Fig. 2 is a cross-section of Fig. 1 on the line a; 00.

A is the levelstock, which is preferably constructed of hard wood thatis not liable to absorb any considerable amount of moisture when exposedto the elements. This stock should be of sufficient length to subserveits use. The stock is rectangular, having parallel sides. At about thecenter of length of the level-stock a rectangular metallic frame, C, isembedded in a suitably-shaped mortise formed in the stock. It isimportant that the top and bottom walls of the mortise just men tionedshould be parallel with the corresponding sides of the level-stock, andalso that the frame 0 should be tightly fitted into the mortise, so thatit will be held in place by its frictional contact with the walls ofthis rectangular slot. As will be seen, the frame C has a rectangularopening formed sidewise through it, thus producing two side and two endwalls, (1, that are respectively parallel. All of the walls cl of frame0 are beveled or cut to slope inward from near their outer edges, thusreducing the Width of the frame to about the diameter of the spirit-tubeB, which will expose this tube on its upper p0r= tion. more completely,and thus permit the air-bubble in it to be viewed plainly from eitherside of the frame.

The spirit-tube B is of such relative length that it may be seated in alongitudinal groove formed in the frame 0, which groove is semi circularin cross-section, and of enlarged diameter as compared to that of thespirit-tube, so that a slightly-elastic bedding material, E,

may be interposed between the metal surface of the groove in the frame 0and the body of the glass spirit-tube B. Y

The bedding-piece E may be made of any proper material-such asvulcanized gum sheeting, leather, or clothand is of such thickness andstability that it will afford a firm support to the tube B, and yet besufficiently elastic to neutralize any shock sus tained by the woodenstock A, and prevent fracture of the tube B.

The spirit-tube is held in place by two sheet-metal straps or bands, a,which are placed over its body near each end, the downwardly-extendedends of said bands being secured to the inclined surfaces of the frame Cby screws 5, as shown in the figures.

It is necessary that the body of the tube B be made of equal diameterthroughout its length, and that the bottom of the groove in the frame 0be parallel with the lower side of said frame, so that if the beddingmaterial is of even thickness it will support the tube in its position,when clamped by the bands at, approximately level, or in a planeparallel to the top and bottom sides of the level-stock A.

Should there be a slight adjustment required to bring the air-bubble cin the center of length of the tube B, when the stock A is located in ahorizontal plane, this can be easily effected by introducing one or moreliners of writing-paper under the low end of the tube, which can besecured to the frame by adjustment of the bands at, as previouslydescribed.

The provision of the bands a and slightly elastic bedding E areimportant features of our present invention, as is also the removablecontinuous bevel-edged frame 0, as by their use a spirit-tube can beseated and properly secured upon a level-stock without the use ofplaster-of-paris or other material which becomes rigid when it sets, andthus renders the spirit-tube liable to breakage from shocks sustained bythe level-stock A.

It is apparent that a precisely-similar frame, spirit-tube, and means ofsecuring the tube in this frame may be set in the level-stock near oneend of the same in a transverse'position, and thus afford means ofindicating a vertical position of the level-stock or deviationstherefrom.

Having fully described our invention, what We claim as new, and desireto secure by Letters Patent, is-- 1. The combination, with alevel-stock, of a rectangular frame having a rectangular hole formed init through its sides that are beveled toward the inner edges of theframe, a

spirit-tube located in a longitudinal groove of the frame, and twostraps that bear on the body of the spirit-tube and are secured neartheir ends to the frame, substantially as set forth. 7

2. The combination, with a level-stock and a rectangular frame which isembedded in the stock and having a rectangular hole with beveled sidesand a longitudinal groove formed in it, of a spirit-tube, aslightly-yielding bedcling-piece, two bands, and screws to secure thebands in place, substantially as set forth. In testimony whereof weaffix our signatures in presence of two witnesses.

EVAN LEWIS. FREDERICK ARMSTRONG. Vitnesses:

JAs. A. ARMSTRONG, ALEX. J. RINGSTROM.

